Aquantum is a unit of:
a. energy
b. speed
c. force
d. radiation

The quantum is generally used for minimum amount of any physical quantity

in terms of physics the quantum is the small unit of energy

generally the energy of each quantum is calculated as

Energy = h x frequency

h = planck's constant

the answer is either b or c

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.